The upper layers have relatively little diversity of colors and textures, but deeper levels show more complex processes. The upper layers could be mostly volcanic while the lower layers were influenced by the period of heavy bombardment and greater interactions with water.

USAGE POLICY
All of the images produced by HiRISE and accessible on this site are within the public domain: there are no restrictions on their usage
by anyone in the public, including news or science organizations. We do ask for a credit line where possible:
NASA/JPL/University of Arizona

POSTSCRIPT
NASA’s Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages the Mars Reconnaissance
Orbiter for NASA’s Science Mission Directorate, Washington. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona.